explain xkcd:Autoconfirmed users
Autoconfirmed users are accounts which are (A) more than three days old and (B) which have at least ten edits. Once a user satisfies these two criteria, they are automatically promoted to the autoconfirmed group, and gain the ability to upload images and files, move pages etc.
A full list of tasks admins can perform can be found at Special:ListGroupRights#Autoconfirmed users.